Gripping and releasing device



March 14, 1944. c, WALKER @annue AND RELEAsme-DEVICE Filed March 27, 1942 ,f /7 ORNEYS.

Patented Mar. 14, 1944 UNITED STATES PATENT OFFICE GRIPPING AND RELEASING DEVICE Clinton L. Walker, Piedmont, Calif. Application March 27, 1942, serial No. 436,484

3 Claims.

My invention relatesv to gripping and releasing devices, and particularly to a tool gripping and releasing device which is employed for lowering a drilling tool into a well and for releasing the tool when lowered and later for engaging and raising the tool.

While gripping and releasing devices oi diierent types have been employed heretofore for accomplishing the same purpose, the present device is of simple and unique construction and is positive in operation. The device embodies a pair of elements having gripping jaws on one end and pivoted near the center to provide a tong-like relationship. A pair of links are also mounted on the pivot by which the tongs are supported. A spring on the opposite end of the tongs from that containing the jaws, forces the ends outwardly .of each other and biases the jaws inwardly or outwardly, depending upon their relationship to each other. The ends of the tongs opposite to the jaws Vhave tapered outer surfaces which may be engaged bythe inner tapered surface of a cuplike element when moved thereover to lock the jaws in releasing position. Camming members are provided on the surfaces of the elements above the gripping jaws `for engagement with a tapered surface on the top end of the tool for forcing the jaws to releasing position. When the opposite ends of the tong elements move to releasing position, the cup-shaped element slides over and engages the tapered surfaces to hold the jaws in non-gripping position.

When the device is to be employed for raising the tool, the cup-shaped clamping element is locked in disengaged position from the tong elements so that the jaws are free to move over the camming surface of the tool and snap into locked position over a ring by which the tool is supported.

The links of the device are attached to a cable by which it may be lowered and raised through the drill stem for lowering a tool to the end of the stem and for engaging and raising the tool when the tool is to be removed from the stem.

Accordingly, one object of my invention is to provide a device for lower-ing and raising a tool through a drill stem.

Another object of my invention is to provide a device formed Iof a pair of elements mounted on a pivot which is ysupported by a pair of links to which a cable is attached.

A further object of my invention is to mount a spring on one end of the tongs which forces the gripping jaws toward gripping position, but which moves the jaws to releasing position when the weight of the tongs forces the jaws over a camming element.

A still further object of my invention is to provide a clamping element on the tongs which retains the gripping end in releasing position after the jaws are released from the end of the tool when the tool has been lowered to the end of the drill stem.

A still further object of my invention is to provide cams on the tongs in position to engage a cam surface of the tool for releasing the jaws from the tool and holding them in released position by a clamping element which moves downwardly over tapered surfaces provided on the opposite end of the tongs.

Other objects and features of novelty of my invention will be either specically pointed lout or will `become apparent when referring, for a ybetter understanding of my invention, to the following description taken in conjunction with the accompanying drawing, wherein:

Figure 1 is a view, partly in section and partly in elevation, of a gripping and releasing device which embodies features of my invention;

Fig. 2 is a side view of the structure illustrated in Fig. 1;

Fig. 3 is a sectional view of the structure illustrated in Fig. 1, taken on the line 3-3 thereof;

Fig. 4 is a view of the structure illustrated in Figs. 1 and 2, as viewed from the lower end thereof; and

Fig. 5 is a broken view with parts in section of a further form of the device embodying my invention.

The gripping and releasing device as illustrated in Figs. 1 to- 4 comprises a pair of elements 6 and 'I near the midpoint of which hinged portions 8 and 9 are provided which nest with eachother and form a hinge when secured together by a pin II. The lowerV portions I2 of the elements 6 and I have projected end portions or jaws I3 which engage the under surface of a collar I4 lon a drilling tool I5. The upper portions I6 and II of the elements 6 and 'I have recesses I8 in which a spring IQvis nested for urging the portions I6 and I1 apart. This moves the end portions I2 inwardly to have the projections I3 engage the body-of the tool I5 beneath the collar I4, as illustrated in Figs. 1 and 2.

A screw 2| limits the movement of the portions .'16 andV I1 away from each other and retains the spring on the axis of the screw. A pin 22 is disposed between the portions I6 and Il for limiting the movement of the elements 6 and 'I as a unit about the pin II. The pin 22 is supported on a pair of links 23 which are pivotally mounted on the pin Ii. The outer surf-aces 24 oi the portions I6 and I1 are tapered and are encompassed by a clamping element 25 of inverted cupshape. A shoulder 26 of the clamping element 25 rests upon the ends of the elements 6 and 1 and prevents the clamping element from engaging the sloping sides 24 and holding the portions I2 apart.

A pin 21 may be placed in an aperture through the clamping element 25 and holes 28 in the links 23 for preventing the downward movement of the element 25 when the device is lowered to grip the` end of the tool. When the end portions I2 of the device are cammed outwardly by a cam surface 29 on the tool, the ends of the portions I5 and I1 move inwardly a sufficient amount to project into the reduced end 3l of the element 25 if the element were permitted to move downward- 1y. The pin 21, however, prevents the element 25 from locking the portions I6 and I1 against separation after they move together and thereby permit the separation and the movement of the projections I3 on the arms I2 to a position under the collar I4 of the tool.

For releasing the device from the tool I provide shouldered semi-cylindrical cam engaging elements 32 which are supported on the inner faces of the end portions I2 by screws 33 and by spring keys 34 which lock the elements 32 against rotation about the screws 33.

When the tool is to be lowered into the well the device is attached to the end of the tool, as illustrated in the figures. The tool and device are then lowered through the drill stem on a cable 36 until the tool reaches its lowermost position. Thereafter the weight of the device will force it downwardly over the camming surface 29 which moves into the cam engaging elements 32 to force the end portions I2 outwardly to move the projections I3 away from the collar I4. The pin 21 was removed :before the lowering operation and, after the portions I6 and I1 have moved inwardly toward each other as the end portions I2 separate, the clamping element is no longer supported by its shoulder 26 and moves-downwardly. The sloping sides 24 of the portions I- and I1 are engaged by the wall ofthe recessed portion 3I to retain the projections I3 in separated position. When the device is moved upwardly thereafter, the projections I3 will pass over the collar I4 and camming portion 29, andwill be separated from the tool I5. The device may then be pulled upwardly out of the drill stem.

When the drilling tool is to be removed from the end of the stem the pin 21 is inserted through the apertures in the element 25 and the links 23 to prevent the clamping element 25 from functioning during the raising operation. The semicylindrical cam elements 32 may also be removed since they perform no functions in the raising operation. The device is lowered through the drill stem until the projections I3 move into engagement with the cam surface 29 of the tool I5, after which the ends I2 are forced apart by the weight of the device, permitting the projections I3 to move over the collar I4. When the device is thereafter drawn upwardly the tool I is carried thereby through the engagement of the projection I3 with the underside of the collar I4.

The device illustrated in Figs. 1 to 4 was invented primarily for use with the drill bit of the collapsible type, illustrated and described in my co-pending application, Serial No. 411,106, filed September 17, 1941. It is to be understood, however, that the device is not restricted in application to this type of drilling tool, as it is very evident that any tool having a cam surface 23 and a collar I4, or similar element, can be raised and lowered by the device herein illustrated and described. The device is positive in operation and is of rigid construction so that no difliculty is experienced in lowering and releasing a drilling tool or for engaging and raising the tool from the end of a drill stem.

In Fig. 5, I have illustrated a gripping and releasing device similar to that of Figs. l to 4, with the exception that the gripping arms 4I and 42 are crossed, in scissors relation, to operate in the opposite direction to arms 6 and 1. Gripping projections 43 extend outwardly of the arms 4I and 42 at the lower end to engage an annular iiange 44 on the inner surface of the supporting tube 45 of the drilling tool. Cam elements 46 are provided above the projection 43 for the purpose of moving the arms 4I and 42 toward each other after the drilling tool is supported on the drill stem to move the projection 43 out of engagement with the annular flange 44. When this occurs, the element 25 locks the arms in their locked together position so that the gripping and releasing device may be removed from engagement with the supporting tube 45 of the drilling tool. When the gripping and releasing device is lowered through the drill stem to engage the supporting tube 45, the element 25 is prevented from functioning by the pin 21 and the projections 43 move over the projection 44 and grip the projection when the gripping and releasing device is raised to raise the drilling tool therewith.

I claim as my invention:

1. A gripping and releasing device including, in combination, a tong element having gripping jaws at one end, a spring for urging said jaws into gripping position, and a locking element having a shoulder resting on the end of the tong remote from the jaw end for sliding over said end and retaining the jaws apart after said jaws have moved out of gripping position and said ends have moved together.

2. A gripping and releasing tool including, in combination, a tong element having gripping jaws at one end, means for supporting said tong element, cam means on said tong element for operating the jaws to non-gripping position, and a locking element carried on the upper ends of the tong element in position to slide over the ends thereof for holding the jaws in non-gripping position after the cam means have moved the jaws to said position.

3. The combination with a drilling tool and a gripping and releasing device, a cam on said tool, a pair of clamping jaws on said device operable by said cam when moved thereover into clamping engagement with said tool, spring means to urge said jaws together, a cam on said device above said jaws also operable by the cam on the tool to move said jaws out of engagement with said tool, and a locking element resting on the ends of the clamping jaws opposite to that engaging the tool to move thereover and retain said jaws in non-gripping position after the disengagement of the device from said tool.

CLINTON L. WALKER. 

